Effect of bevelling of carbide turning inserts on chip formation and cutting forces

Abstract

The sharp cutting edges of tool inserts are usually bevelled for improving the tool life mainly through edge-strength, better heat dissipation, restricted contact cutting effect and favourable distribution of stresses in the cutting tools. In the present work the sharp edges of carbide inserts have been bevelled with varying angle and width. Plain carbon (C −0.25%) steel rods were machined by those modified turning inserts at various speeds, feeds and depths of cut. The effects of variation of the geometrical and process parameters on chip reduction coefficient, chip contact length and cutting forces were observed. The statistical analysis of the data obtained by designed experiment have revealed some interesting and important results, which have been reported in this paper. Both chip reduction coefficient and chip contact length were found to change favourably by the incorporation of land with appropriate angle and width. Though the thrust force increased, the main (tangential) cutting force decreased with the increase in land width up to certain extent and beyond that increased mainly due to negative rake effect.